The present invention relates to a power transmission unit for automotive vehicles, and more particularly to an improvement of a power transmission unit of the type which includes a change-speed mechanism arranged for being drivingly connected to an engine by a friction clutch assembly and a final drive gearing connected to an output shaft of the change-speed mechanism to drive a differential gear unit at a selected speed ratio.
In such a conventional power transmission unit as described above, torsional rigidity of the drive power train is relatively high, causing unpleasant noises or extraordinary vibration at respective connections of the drive power train. To reduce the undesired noises and vibration, a certain number of damping springs have been assembled within the friction clutch plate to reduce the torsional rigidity. It has, however, been experienced that the assembled damping springs in the clutch plate increases its inertia moment and enlarges the capacity of the clutch assembly.